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You can use all types of paint for your Gunpla. It’s a matter of what paints are available to you, how you gonna apply them and what are the conditions you’re going to work in.
For example, indoor without any sort of ventilation? Then using water based acrylics for airbrushing if you have to consider other people as these smell the less and are pretty “healthy”.
Indoor with an extractor booth and respirator? Any type of paint you want.
Outdoor with or without respirator? Spray cans, airbrush, the lot.
Or will you be hand painting? All types of paint wil do. Remember that some paints may stink up the house somewhat, so keep it contained to a well ventilated area, especially for yourself with paints in such close proximity. Just dilute the paint and brush on multiple coats to get a result without brush marks. Some paints tend to dry too fast so working with them might be a challenge without mixing in any retarder.
If you could be a bit more specific, I could give you some more advise instead of some general stuff 😉